1. Field of the Invention
This invention relates to a fastener device, and more specifically, to a device that can capture and hold a standard internally wrenched fastener without requiring a specially configured fastener.
2. Prior Art
Various captive fasteners are known in the art including those illustrated and described in U.S. Pat. Nos. 6,086,480, 6,074,146, 5,743,692, 5,642,972, 5,611,654, 5,382,124, 5,338,139, 5,336,028, 4,616,967, and 2,921,616. These designs typically include a specially prepared fastener held captive by a threaded bushing. This arrangement requires the diameter of the fastener under the head to be reduced in order for the head to have adequate contact with the bushing. This reduction in diameter is believed to result in an undesirable strength reduction.
The traditional captive fastener devices are not constructed with off-the-shelf components, especially the threaded fastener portion. Secondly, the traditional captive fastener device has a spring which terminates under a lip of the head of the fastener. Accordingly, either
the housing extends the distance of the head of the fastener in addition to the length of the spring, or the housing terminates at the lip of the head of the fastener. In both configurations, the assembly extends the length of the spring AND the length of the head of the fastener. Furthermore, prior art captive fastener devices are not able to utilize springs having diameters greater than the diameter of the head of the fastener.
A need exists for a cost effective captive fastener device which may utilize standard fasteners.
Another need exists for a captive fastener device design which may be relatively easily assembled.
A further need exists for a captive fastener device that can utilize springs having an inner diameter which is greater than the diameter of the fastener.
Consequently, it is a primary object of the present invention to provide a captive fastener device which may utilize a standard fastener.
Another primary object of the present invention is the ability to utilize springs of larger diameters than the fastener.
Accordingly, the present invention provides a captive fastener device for holding two members together. The device is comprised of a housing which may be securely attached to the first member. Within the housing is a spring which biases a bottom of a first lip of a cup washer. The top of the first lip contacts the top of the housing when the fastener is not engaged. The fastener has a lip at the bottom of the fastener head which rests on a top surface of a second lip of the cup washer. The bottom of the second lip contacts the first member when the fastener has fully engaged the second member to secure the first and second members together. The first lip of the cup washer has a greater diameter than the second lip.